It's true that the compliments forum is for people to say what they like about the game. Would I say it's a place for constructive feedback probably not. However it is a place to say what you like. I'd consider it a place for happy thoughts that doesn't need structure to the posts. Suggestion forums are typically a place for making the game better with constructive feedback whether positive or negative. If you read the small header under the compliments forum from the forum main page it says
tell us what you like
if it becomes a nuisance we can always revisit the subject.
When the day becomes the night and the sky becomes the sea, when the clock strikes heavy and there’s no time for tea; and in our darkest hour, before my final rhyme, she will come back home to Wonderland and turn back the hands of time.